president barack obama and republican presidential hopeful mitt romney will square off on the issues in their first side- by-side showdown of this race. >> i think the winner will be declared by the american people based on what the two candidates say and who lays out a vision for the future, some policy details. >> tonight the debate will focus on domestic issues including the economy, health care, and the role of government. the candidates are preparing and many are weighing in on what they need to do. >> i don't think mitt romney has to win this debate. he needs to show that he is presidential and compassionate. >> the president is all about his mannerisms and his style. i think he cannot come across as charitable or impatient. he has to act like he wants to be there and maybe smile a lot. >> tonight could be a critical moment. for both moment according poll, mr. obama holds a 51% to 43% lead in ohio. in virginia and florida, romney is also trailing, but the numbers are much closer. >> he's behind because this has become a referendum on. on >> obama and romney are expected to take